Rock-drill bit.



A. S. MEGUIRE.

ROCK DRILL BIT. APPLIOATION FILED JAN. s, 19%.

1,086,673 Patenm Aug. 27, 1912.

zwA/M @uww. 07 7% citizen of the l Elneeification 013 Letters Patent.

Patented filing 2'1, tillfi.

llgng'lication filed innnary t3, 1am. serial Ho: $59,919.

To all whom it way women:

lle it, lniown tint ll. nnia'aii S. illnonuin, nited Wales, residing at ihirago in the county oi Cook and State of Illinois, have imented rertain new and use fol lnipi'ovenients in lioelelllrill "Bits, of whieh the lolhnvingg; is a specification.

This invention relates to improvements in rorl: drill. bits and th especial oh'ect of the inmrovenn-nts whiz-h form the so act inat-,

ter of this applica ion is to produce a bit that l have an elm-lent matting edge with ing' the iiinmetei 'ot the head and V .i a uniform size or diameter ole produced hy the drill.

V .h-er ohjoet is to provide a hit that will ho s nn an well as durable and which will not m'e frequent sharpening. In hits commonly used the cutting edges are usually ll-shaped in ci oss section and the ex treinities or corners soon wear away and become rounded until they are worn down to the width of lhe hase of the anglewhioh forms the cutting; surface with the result that they olo not eat the rock but merely pound or pnlverize it and as the diameter of the hit is greatest at the apex of the cutting edge the wearing away of these points materially din'linishes the diameter of the hole prodneed hy the hit so that it gra dually grows sn'ialler as it goes deeper into the rock unless of coarse fresh hits are used from time to time.

The primary ()llji'Ct of my invention is to provide a hit that will avoid the objections common to the hits now in use and one that will maintain its cross especially and effective cutting surface diameter throinzhont practically the entire life of the hit and thus avoid the necessity of sharpeninn with its lillfitl-Qflil heating and reheating which as well known impairs the quality oil-the metal and results in a very metlicient hit shown in Fig. 1; Fig. 3 shows a slightly modified form of hit embodying my invention; Fig. at is an and "view of the bit shown In Fig. 3;.and Fig/n is a persper-tive and my invention showing a different manner of attaching the hie to the stock or rod.

My improved hit may he made of any suitable material and of any desired size or general shape in cross section.

Referring to Fig l and 2. it will be seen that the general (-ross sectional area of my improved hit is ri-rtangnlar in llnit it is formed at its heel portion with four flat, faces (5. Flanking these llat faces and No tending suhsta nlially the length of the hit are grooves 7 the sides of which extend from the edges of the {lat portion (3 on one side to ribs 8 whirh extend longitlnlinally throughout the length of the hit. Four re-- cea es 9 are fornn'd lwlween the rihs 8, said reg'esses starting in the ilat tat-es i and extending forwardly and flaring outwardly to the eiztrennouter end of the hit with grail ually inrreasing depth. min-ate in interserling diagonal eross ribs which at their extreme mile! ends are sul stantially the thirkness of the longitui'linal ribs 8.

it will he apparent that in a hit cont uct d as above desrrihed tho otlertive cutting edges or rlhs 8 will he maintained until the hit is practically used up. it will also he ohvions that as the rihs 10 at the end of the bit are worn away the recesses 9 will maintain Qil@('ll,\'0 cutting sin-laws at the ends of the hit though not as sharp as the.

edges of a new tool unless the recesses 9 are I maintained at their normal depth by regrinding from time to time as the tool heconies worn.

Referring to Figs. 3 and il, the ribs 10 at the end of the hit are identical in arrangeinenh'size and rotting etli-iz'iency with those shown in Fig. 1 except that as the grooves 9 are made deeper the ribs are thinner and hence the rutting etliriency at the end of the bit is prolonged tor a greater length of time than with the form shown in Fig. l. The ribs 8 which extend longitudinally at the corners of the rectangnhu' hlock whieh forms the bit'shown in Fig". 3 are without the r'hannels of grooves 'l but it will be obvious the rihs or cutting edges 8 will be maintained throughout practically the entire life of the hit. lit will he seen that with the exception of the area of the recesses 9 and the absence of the channels or grooves 'lhese reresses tersectional view of another modified form of a 7 the bit shown in Figs. 3 and 4 is substan tially identical Figs. 1 and 2. g I

Referring to Fig. 5 the ribs at the end of the bit are identical with those shown in Figs. 1 and 3, but the recesses 9 are shalwith the design shown in lower and do not extend longitudinally the bit from being defiecteddaterally in its optel-mined largelg erations as they form a longitudinal bear-.

ing or guide for the to ol in the socket or hole which is being drllled, and therefore serve to maintain the bit in the plane atwhich it is started in the rock being drilled. In addition to serving as means for maintaining the integrity of the longitudinal ribs 8, 8 8", the recessed sides of the bit serve as clearances for the rock articles which result from the operations of the bit.

The particular design or formation of bit within the scope of my invention will be deupon the character of the rock that may e operated upon, that is to say for some forms of rock one design of bit will be more efficient than another in'that the cutting portion will be either sharper or stronger than any other forms. In all of the forms disclosed herein, there are present parallel cutting edges which extend longitudinally throughout the entire length of the bit and thin cutting ;.wings which are equal in length to the greatest width or cross diameter of the body of the bit. These wings are formed by the metal left between the several grooves or depressions 9, 9, and 9". As shown in Fig. 1, the wings extend The concave faces 6 are substaning convex. In Fig. 3, the walls are concave throughout, while in Fig. 5, the walls are concavo-convex. In Figs. 1 and 3, the

grooves extend inwardliy a substantial distance, while in Fig. 5, t grooves 9 terminate a short distance from the edges 10.

These differences in contour are mainly matters of. degree or extent. In 'all cases the cross-sectional area of the wings gradually increase as the extremity of the bit is worn away. As my bit is primarily intended for use with reciprocating drills with merely incidental rotary movement, the Walls ofthegrooved portions gradually wear away with the other portions, so they recede and thus the effectiveness of the wings is prolonged though in lessening degree.

The bits shown inFigs. 1 and 3 may be connected with shanks or drill-bars'in any suitable manner either by inserting the bail or shank in a socket formed in the bit, or

inserting a portion of the bit in a socket in the bar, such connection however forms no part of this invention.

Having thus what I claim is e A drill bit substantially rectangular in cross section and having thin cutting ribs with parallel side walls and extending longitudinally thereof with recesses in the sides of said bit between said ribs, said recesses being deepest at the cutting end of the bit and of graduallydiminishing depth rearwardly or toward the heel of the bit, and having transverse cutting ribs at the outer end of the bit, said ribs having their cutting edges at right angles to the cutting edges of the longitudinal ribs.

In testimony in the presence of two witnesses.

ABIJAH S. MEGUIRE. -Witnesses:v

M. A. MILORD, WM. HAROLD EICHELMAN.

whereof I aflix my signature described my invention, 

